1. Field of the Disclosure
The present disclosure relates generally to a circuit protection system and a method for over-current and over-voltage protection for communication cabling medium and various traditional and emerging cable construction and materials of emerging devices. Emerging devices include, but are not limited to, currently known devices using Power over Ethernet (PoE) technology. More particularly, the present disclosure relates to a circuit protection system and a method to provide over-voltage and/or over-current protection for communication circuits and associated wires and conductors, especially, for the current National Electrical Code (NEC) classification Chapter 7 class 2 & 3 circuits and Chapter 8 communication circuits. A protection module of circuit protection system is disposed at any point between a power supply and a powered device and can limit the electrical current allowed to pass into the circuit based on the physical construction, wire gauges, and other factors representing the limitations of communication cabling medium. Further, circuit protection system has an ability of detecting heat rise of communication cabling medium and provides a maximum temperature threshold disconnect that allows for protection of thermal degradation of the communication cable medium.
2. Description of Related Art
Traditionally, communication circuits and associated wires and conductors were designed and intended for transmission of low power (i.e. phantom voltage) and data communication signals, and cabling systems and components were not originally designed to transmit high levels of power.
Unfortunately, current electrical and building codes and standards do not address the issue of utilizing communication cables (e.g., twisted pair based and/or coaxial cables) and their conductors as a power transmission medium. Nowadays there is an overwhelming trend in the market to utilize low voltage power communication cabling medium to replace wiring systems that have traditionally been relied upon to transmit high voltage alternating current (AC) power. These systems include, but are not limited to, computers, room and building lighting, remote cameras, wireless access points, patient monitoring systems, access card readers, building automation systems, and others. Unlike many traditional higher voltage AC wiring systems, equipments based on many of new technologies can be accessed by all members of a family including very young children. For example, many families allow their very young children to operate all aspects of the family IPad® including plugging and un-plugging from a charging station. The common belief is that these coaxial cables and/or twisted pair based cables are non-power outlets and therefore they will not hurt people. However, as the trend toward PoE and similar technologies continue to evolve, without a circuit protection system, the equipment accessible to people can possibly result in significant damage.
With the current environment of rapid innovation within this vertical market, it will become increasingly difficult to regulate or enforce power based safety issues. An example of this difficulty is to check a code compliant communication system that has been installed within a facility today. If the manager of this facility decides to have a large reduction in operating expense by implementing PoE or similar technologies, which is up to 30 watts today, throughout this facility, there will be no issue with the manager's plan, since the communication network was installed and the building received its Certificate of Occupancy (CO). Generally, before the approval of the occupancy of any building structure, the Authority Having Jurisdiction (AHJ) needs to inspect facility structures to ensure that they comply with applicable safety codes and requirements. Receiving the CO certifies means that the structure or building has passed all of the required fire and safety inspections. However, it can still present many fire and safety problems if the next manager decides to install PoE++ or other powering technologies, which can be possibly up to 200 watts, since communication systems, including the cabling systems, were not originally designed to transmit such high power levels, and the cabling systems are located inside the walls and the detailed information about the cabling systems cannot be obtained easily.
As the power continues to increase within these cabling systems, ancillary ramifications will emerge. The heat generated by the power transmission will rise across the circuit and its components. The increase in heat can cause a vastly increased rise in temperature when these twisted pairs and coaxial cables are bundled such as in a riser, trunk, composite design, or when implemented in combined pathways. These pathways can include, but are not limited to, cable tray, flexible conduit and ridged conduit systems. The heat rise has the potential to melt current insulation and jacketing materials, and can possibly result in a condition of arcing and eventual fire. Moreover, environmental factors such as ambient air temperature and weather conditions can contribute to increased heat generation in cables.
Accordingly, there will be a need for over-voltage, over-current, and power limiting protection for life safety and/or equipment failures. It is desirable to have an over-current limiting control point within the circuit protection system to allow protection for the physical cables and conductor media, active equipment and persons, and help people implement life safety regulations.